"A particle P is projected with speed 12 ms-1 up a line of greatest slope of a fixed smooth plane inclined at an angle of theta degrees to the horizontal. The speed of P after 2 seconds is 4.8 ms-1. Find, to 2sf, the value of theta. "
I've worked out the acceleration (-3.6 ms-2), but I'm not sure what I'm supposed to do next really - I don't have a mass, force etc. It may involve simultaneous equations, but I'm not sure what equations to use.